1. Field of the Invention
The present invention relates to a process for preparing fibrous alkali metal titanate which is useful as a heat resistant and heat insulating material.
2. Description of the Prior Art
Alkali metal titanates are compounds having the formula: EQU M.sub.2 O(TiO.sub.2).sub.n
wherein M represents an alkali metal and n is from 1 to 7. Heretofore, fibrous alkali metal silicates have been prepared by using the flux method, the hydrothermal method or the calcination method.
From the industrial viewpoint, the flux method and the calcination method are superior to the hydrothermal method which uses an expensive and danger autoclave. In the former methods, continuous operation on a large scale can be attained.
However, the calcination method has the disadvantage of preparing only microscopic size fibrous alkali metal titanates, though the process is simple because of the solid phase reaction.
The conventional flux method has the disadvantage of pollution caused by the large amount of toxic gas produced by the fluorine and chlorine containing components of the flux during the operation because an alkali metal halide such as potassium fluoride, potassium chloride, etc. is used under high vapor pressure.